Cupric chromate, preparation

Copper chromite (Lazier catalyst). Supplier Harshaw (CU-0202P 556-002). For preparation of the catalysC an aqueous solution of barium nitrate and cupric nitrate trihydrate is stirred during addition of a solution of ammonium chromate, prepared from ammonium dichromate and aqueous ammonia. The reddish brown precipitate of copper barium ammonium chromate is washed and dried and decomposed by heating in a muffle furnace at 350-450 . The ignition residue is pulverized, washed with 10% acetic acid, dried, and ground to a fine black powder. 

Dissolve 15-0 g. of A.R. barium nitrate and 130 g. of A.R. cupric nitrate trihydrate in 450 ml. of water at 80°. Prepare a solution of sodium chromate by dissolving 89 g. of recrystallised sodium dichromate dihydrate in 200 ml. of water and adding 112 5 ml. of cone, ammonia solution (sp. gr. 0-90). Add the warm solution (80°) of nitrates in a thin stream, with stirring, to the sodium chromate solution (at 25°). Collect the orange precipitate by suction Bltration, wash it with two 50 ml. portions of 5fiter, drain well, and dry at 75-80° for 12 hours powder finely. 

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